Thomas Andrillon, Daniel Pressnitzer, Damien Léger & Sid Kouider (2017) Formation and suppression of acoustic memories during human sleep, Nature Communications 8, Article number: 179

Résumé :
Sleep and memory are deeply related, but the nature of the neuroplastic processes induced by sleep remains unclear. Here, we report that memory traces can be both formed or suppressed during sleep, depending on sleep phase. We played samples of acoustic noise to sleeping human listeners. Repeated exposure to a novel noise during Rapid Eye Movements (REM) or light non-REM (NREM) sleep leads to improvements in behavioral performance upon awakening. Strikingly, the same exposure during deep NREM sleep leads to impaired performance upon awakening. Electroencephalographic markers of learning extracted during sleep confirm a dissociation between sleep facilitating memory formation (light NREM and REM sleep) and sleep suppressing learning (deep NREM sleep). We can trace these neural changes back to transient sleep events, such as spindles for memory facilitation and slow waves for suppression. Thus, highly selective memory processes are active during human sleep, with intertwined episodes of facilitative and suppressive plasticity.

Ángel Gómez, Lucía López-Rodríguez, Hammad Sheikh, Jeremy Ginges, Lydia Wilson, Hoshang Waziri, Alexandra Vázquez, Richard Davis & Scott Atran (2017) The devoted actor’s will to fight and the spiritual dimension of human conflict, Nature Human Behaviour 1, 673–679

Résumé :
Frontline investigations with fighters against the Islamic State (ISIL or ISIS), combined with multiple online studies, address willingness to fight and die in intergroup conflict. The general focus is on non-utilitarian aspects of human conflict, which combatants themselves deem ‘sacred’ or ‘spiritual’, whether secular or religious. Here we investigate two key components of a theoretical framework we call ‘the devoted actor’—sacred values and identity fusion with a group—to better understand people’s willingness to make costly sacrifices. We reveal three crucial factors: commitment to non-negotiable sacred values and the groups that the actors are wholly fused with; readiness to forsake kin for those values; and perceived spiritual strength of ingroup versus foes as more important than relative material strength. We directly relate expressed willingness for action to behaviour as a check on claims that decisions in extreme conflicts are driven by cost–benefit calculations, which may help to inform policy decisions for the common defense.

Guillaume Dezecache, Julie Grèzes, Christoph D. Dahl (2017) The nature and distribution of affiliative behaviour during exposure to mild threat, Royal Society Open science, v4 (8): 170265

Résumé :
Individual reactions to danger in humans are often characterized as antisocial and self-preservative. Yet, more than 50 years of research have shown that humans often seek social partners and behave prosocially when confronted by danger. This research has relied on post hoc verbal reports, which fall short of capturing the more spontaneous reactions to danger and determine their social nature. Real-world responses to danger are difficult to observe, due to their evanescent nature. Here, we took advantage of a series of photographs freely accessible online and provided by a haunted house attraction, which enabled us to examine the more immediate reactions to mild threat. Regarding the nature and structure of affiliative behaviour and their motivational correlates, we were able to analyse the distribution of gripping, a behaviour that could either be linked to self- or other-oriented protection. We found that gripping, an affiliative behaviour, was common, suggestive of the social nature of human immediate reactions to danger. We also found that, while gripping behaviour is quite stable across group sizes, mutual gripping dropped dramatically as group size increases. The fact that mutual gripping disappears when the number of available partners increases suggests that gripping behaviour most probably reflects a self-preservative motivation. We also found age class differences, with younger individuals showing more gripping but receiving little reciprocation. Also, the most exposed individuals received little mutual gripping. Altogether, these results suggest that primary reactions to threat in humans are driven by affiliative tendencies serving self-preservative motives.

C. van den Driessche, M. Bastian, H. Peyre, C. Stordeur, E. Acquaviva, S. Bahadori, R. Delorme and J. Sackur (2017) Attentional Lapses in Attention Deficit / Hyperactivity Disorder: Blank Rather than Wandering Thoughts, Psychological Science, online first

Résumé :
People with attention-deficit/hyperactivity disorder (ADHD) have difficulties sustaining their attention on external tasks. Such attentional lapses have often been characterized as the simple opposite of external sustained attention, but the different types of attentional lapses, and the subjective experiences to which they correspond, remain unspecified. In this study, we showed that unmedicated children (ages 6–12) with ADHD, when probed during a standard go/no-go task, reported more mind blanking (a mental state characterized by the absence of reportable content) than did control participants. This increase in mind blanking happened at the expense of both focused and wandering thoughts. We also found that methylphenidate reverted the level of mind blanking to baseline (i.e., the level of mind blanking reported by control children without ADHD). However, this restoration led to mind wandering more than to focused attention. In a second experiment, we extended these findings to adults who had subclinical ADHD. These results suggest that executive functions impaired in ADHD are required not only to sustain external attention but also to maintain an internal train of thought.

Palminteri S, Lefebvre G, Kilford EJ, Blakemore SJ. (2017) Confirmation bias in human reinforcement learning: evidence from counterfactual feedback processing. PLOS Computational Biology, 13(8): e1005684

Résumé :
Previous studies suggest that factual learning, that is, learning from obtained outcomes, is biased, such that participants preferentially take into account positive, as compared to negative, prediction errors. However, whether or not the prediction error valence also affects counterfactual learning, that is, learning from forgone outcomes, is unknown. To address this question, we analysed the performance of two groups of participants on reinforcement learning tasks using a computational model that was adapted to test if prediction error valence influences learning. We carried out two experiments: in the factual learning experiment, participants learned from partial feedback (i.e., the outcome of the chosen option only); in the counterfactual learning experiment, participants learned from complete feedback information (i.e., the outcomes of both the chosen and unchosen option were displayed). In the factual learning experiment, we replicated previous findings of a valence-induced bias, whereby participants learned preferentially from positive, relative to negative, prediction errors. In contrast, for counterfactual learning, we found the opposite valence-induced bias: negative prediction errors were preferentially taken into account, relative to positive ones. When considering valence-induced bias in the context of both factual and counterfactual learning, it appears that people tend to preferentially take into account information that confirms their current choice.

Salvador A, Worbe Y, Delorme C, Coricelli G, Gaillard R, Robbins TW, Hartmann A, Palminteri S. (2017) Specific effect of dopamine partial agonist on counterfactual learning: evidence from Gilles de la Tourette syndrome. Scientific Reports; 7: 6292.

Résumé :
The dopamine partial agonist aripiprazole is increasingly used to treat pathologies for which other antipsychotics are indicated because it displays fewer side effects, such as sedation and depression-like symptoms, than other dopamine receptor antagonists. Previously, we showed that aripiprazole may protect motivational function by preserving reinforcement-related signals used to sustain reward-maximization. However, the effect of aripiprazole on more cognitive facets of human reinforcement learning, such as learning from the forgone outcomes of alternative courses of action (i.e., counterfactual learning), is unknown. To test the influence of aripiprazole on counterfactual learning, we administered a reinforcement learning task that involves both direct learning from obtained outcomes and indirect learning from forgone outcomes to two groups of Gilles de la Tourette (GTS) patients, one consisting of patients who were completely unmedicated and the other consisting of patients who were receiving aripiprazole monotherapy, and to healthy subjects. We found that whereas learning performance improved in the presence of counterfactual feedback in both healthy controls and unmedicated GTS patients, this was not the case in aripiprazole-medicated GTS patients. Our results suggest that whereas aripiprazole preserves direct learning of action-outcome associations, it may impair more complex inferential processes, such as counterfactual learning from forgone outcomes, in GTS patients treated with this medication.

Philippe Schlenker (2017) Outline of Music Semantics, Music Perception: An Interdisciplinary Journal, Vol. 35 No. 1; (pp. 3-37)

Résumé :
We provide the outline of a semantics for music. We take music cognition to be continuous with normal auditory cognition, and thus to deliver inferences about “virtual sources” of the music. As a result, sound parameters that trigger inferences about sound sources in normal auditory cognition produce related ones in music. But music also triggers inferences on the basis of the movement of virtual sources in tonal pitch space, which has points of stability, points of instability, and relations of attraction among them. We sketch a framework that aggregates inferences from normal auditory cognition and tonal inferences, by way of a theory of musical truth: a source undergoing a musical movement m is true of an object undergoing a series of events e just in case there is a certain structure-preserving map between m and e. This framework can help revisit aspects of musical syntax: Lerdahl and Jackendoff’s (1983) grouping structure can be seen to reflect the mereology (“partology”) of events that are abstractly represented in the music. Finally, we argue that this “refentialist” approach to music semantics still has the potential to provide an account of diverse emotional effects in music.

Philippe Schlenker (2017) Sign Language and the Foundations of Anaphora, Annual Review of Linguistics, Vol. 3:149-177

Résumé :
Sign language anaphora is often realized very differently from its spoken language counterpart. In simple cases, an antecedent is associated with a position or “locus” in signing space, and an anaphoric link is obtained by pointing toward that locus to recover its semantic value. This mechanism may sometimes be an overt realization of coindexation in formal syntax and semantics. I discuss two kinds of insights that sign language research can bring to the foundations of anaphora. First, in some cases the overt nature of indices in sign language allows one to bring overt evidence to bear on classic debates in semantics. I consider two: the availability of situation-denoting variables in natural language and the availability of binding without c-command. Second, in some cases sign language pronouns raise new challenges for formal semantics. Loci may function simultaneously as formal variables and as simplified depictions of what they denote, requiring the construction of a formal semantics with iconicity to analyze their properties.

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